Remove Global Drafts Feature Flag (#23767)

* Remove global draft feature flag

* More removal - in progress

* Removed the rest in webapp

* Removed the rest in webapp

* Fix tests

* Update feature_flags.go

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Co-authored-by: Mattermost Build <build@mattermost.com>

e2e-tests/playwright/support/server/default_config.ts

@@ -677,7 +677,6 @@ const defaultServerConfig: AdminConfig = {
         PeopleProduct: false,
         ReduceOnBoardingTaskList: false,
         ThreadsEverywhere: false,
-        GlobalDrafts: true,
         OnboardingTourTips: true,
         DeprecateCloudFree: false,
         CloudReverseTrial: false,